This invention relates to a fixing device for electrophotography, and more particularly to a contact-heating type fixing device employing a heated roll.
In a contact-heating type fixing device, it has been heretofore required to form a thin film of an offset phenomenon preventive liquid such as a silicone oil on a heated roll for the purpose of preventing deposition of a viscous material such as a toner on the surface of the heated roll (the deposition will be hereinafter referred to as "offset"). In order to supply the offset preventive liquid, it is the general practice to supply the offset preventive liquid continuously to a cleaning member of heat resistant felt or the like with use of a feed roller. The role of the cleaning member of the heat resistant felt material is twofold, one being to clean off a toner which is offset onto a heated roll and the other is to supply the offset preventive liquid uniformly to the heated roll. However, known offset preventive liquid supplying means have various defects, that is to say; they allow deposition of offset toner on the cleaning member during use over a long period of time until it becomes utterly impossible to supply the offset preventive liquid; they are incapable of supplying the offset preventive liquid uniformly over a long time period, forming stains on duplicated sheets due to an excessive feed or failing to give satisfactory offset preventive effects due to an insufficient supply, and they require provision of a container or the like for holding the offset preventive liquid.